Propagation of a solitary wave over a finite submerged thin plate

Abstract

For the purpose of this paper, the in-house large-eddy simulation code, Hydro3D, is refined to study wave structure interaction. First of all, the code is used to develop a numerical wave tank capable of simulating accurately the generation, progression and damping of solitary waves in a tank. Then, Hydro3d is employed to simulate a previous laboratory experiment of a wave propagating over an infinitely wide flat plate. The code’s accuracy is validated by comparing computed waterlevels and hydrodynamic forces on the plate with measured data for which good agreement is found for a number of conditions (i.e. varying wave steepness or plate submergence, respectively). Then the study is extended to investigate three-dimensional effects for which the infinitely wide plate is replaced by a finite square plate. It is found that the pressure difference between the lower and upper side of the plate drives a span-wise flow and creates unique flow structures and water-surface fluctuations near the plate due to the three-dimensionality of the problem. A further three-dimensional study is conducted for which the finite plate is fixed at an angle of attack in respect to the incident wave and variations in hydrodynamic forces and free-surface elevations are computed. Both vertical and horizontal forces are reduced when the plate is fixed at 45∘ degrees and minor water-level fluctuations appear, reflecting the pattern of the rotational flow near the plate edges. Plots of the velocity vectors, swirl-strength, pressure and wave elevation and acting forces reveal significant differences between an infinitely wide and a finite square plate subjected to a solitary wave.